1. Field of the Invention
The present invention is directed, in general, to computer systems and, more specifically to a frame structure for mounting a computer peripheral device and chassis therefor within a bay in the frame.
2. Description of the Related Art
Computer systems are information handling systems which can be designed to give independent computing power to one user or a plurality of users. Computer systems may be found in many forms including, for example, mainframes, minicomputers, workstations, servers, personal computers, internet terminals, notebooks and embedded systems. Personal computer (PC) systems, such as the International Business Machines (IBM) compatible PC systems, include desk top, floor standing, or portable versions. A typical PC system is a microcomputer that includes a microprocessor, associated memory and control logic and a number of peripheral devices that provide input and output (I/O) for the system. Such peripheral devices often include multiple I/O devices such as display monitors, keyboards, pointer type input devices such as mice, touchpads and electronic pens, floppy and hard disk drives, compact disk read only memory (CD-ROM) drives and printers. Other I/O devices include various communication devices such as digital communication/network connection devices and modems, sound and video I/O devices such as speakers, microphones, voice recognition devices, digital cameras, scanners, televisions and videocassette recorders, and mass storage devices such as tape drives, CD-recordable (CD-R) drives or digital video/variable drives (DVDs).
As indicated, computer systems utilize a number of storage mediums and associated devices to store and provide data required by the system and its users. For example, a network server is a focal point for processing and storage in the network, as the network server is responsible for distribution of application programs and data to the client PCs. Since they must serve as a focal point, network servers are typically outfitted with the latest, fastest, largest central processing unit ("CPU"), buses and random access memory ("RAM"). Further, such network servers are provided with at least one (and almost always more than one) large, fast hard disk drive providing nonvolatile storage for the application programs and data.
Network servers often employ more than one disk drive for three reasons. First, storage needs may exceed the capacity of today's largest single drives. Second, large drives are often more expensive per unit of storage than smaller drives. Third, it is advantageous from the standpoint of reliability to spread the application programs and data over multiple disks such that, if one disk fails, all is not lost. In fact, it has been recognized that an array of relatively inexpensive disks may act in concert to provide nonvolatile storage that is faster and more reliable than a single large expensive disk drive.
The technology to enable such inexpensive disks to cooperate advantageously is generally known as Redundant Array of Inexpensive Disks ("RAID") and is particularly useful in the environment of network servers. RAID provides data redundancy, such that if a single disk drive fails, the data stored thereon can be reconstructed from the data stored on the remaining disks. There are several levels of RAID, depending upon the degree of speed and reliability desired. The reader is directed to widely-available publications on RAID and the advantages thereof, as a general description of RAID is outside the scope of the present discussion.
In the most sophisticated network servers, a failed disk drive can be replaced and the data thereon restored by software without interrupting the server's operation. In so-called "hot plugging," the failed disk drive is removed and a new one installed in its place without cutting off the power to the drive.
Typically, a network server is advantageously housed in a main chassis, most often in the form of a tower, containing multiple bays for receiving the various hard disk drives that comprise the network server's nonvolatile storage. It is desirable to provide a rapid, convenient means of installing disk drives in, and removing disk drives from, the bays. It is also desirable that these devices are easily accessible so as to not disturb the other devices or the system as a whole when they are inserted or removed. It is especially desirable in the context of RAID, wherein a drive may be hot-plugged into the bay. Accordingly, computer manufacturers have begun to provide external openings in computer chassis which provide direct access to the bays and the devices located therein without requiring access to other components of the computer system.
In order to insert these devices into their respective bays, carriers are frequently used as platforms to hold each device. These carriers are designed to secure each device and provide for smooth insertion into a bay and to assure a proper electrical connection between the device and the system. However, most carrier designs require the individual inserting the device to apply force directly to the carrier, either through pushing or pulling, to connect the device to the computer system, usually by a male connector on the back of the device and a female connector on a system board at the back of the bay. Further, in an attempt to insert or remove a device from the system, the individual often applies force to the device in a direction non-parallel to the connector. By application of such forces connector pins are often bent and the stress placed on the system board, into which the device is connected, can lead to system failures.
A well-designed structure for removably mounting a disk drive chassis within a bay should provide mechanics advantage for ease of insertion and removal of the chassis. This reduces the force a user is required to exert to install or remove the chassis. Second, such a structure should provide self-alignment for a carrier that cradles the chassis. Self-alignment ensures proper position and orientation for the chassis carrier and any movable parts associated with the chassis carrier (such as the mechanism affording mechanical advantage). Third, the structure should provide positive latching for retaining the chassis in place once installed. Fourth, the structure advantageously connects the chassis carrier to computer system ground. Fifth, the structure advantageously discharges static electricity.
FIG. 1A shows a computer system frame 100 which contains a plurality of bays 102, 104, 106. As shown, only bay 106 contains a hard disk drive chassis 114. Each bay 102, 104, 106 has mounted therein a pair of mounting rails 120a, 120b, 122a, 122b, 124a, 124b. The mounting rails 120a, 120b cooperate to provide a guide path within the bay 102 for a chassis carrier such as chassis carrier 134 in bay 106. Likewise, the mounting rails 122a, 122b and the mounting rails 124a, 124b cooperate to provide guide paths in the bays 104, 106 respectively, for other chassis carriers, including a chassis carrier 134 shown in a mounted position within the bay 106 and cradling the hard disk drive chassis 114.
Frame 100 includes lances 101, 103, 105 for each of bays 102, 104, 106, respectively. Lances 101, 103 and 105 are metal arcs depressed toward the inside of frame 100 by deforming the sheet metal surface of frame 100. The lances provide static discharge and grounding for electronic devices carried by chassis carriers inserted into the bays (e.g., chassis carrier 134). Each such lance is a contiguous strip of sheet metal deformed from the plane of sheet metal which is the surface of frame 100. Such lances have been found to neck down when deformed from the plane of the sheet metal. When the sheet metal is stretched, the sheet metal lance necks down such that material is taken from the width of the lance and displaced to accommodate the increased length of the lance. For example, as shown in FIG. 1B, the width of the lance decreases from a width A at the base of the lance to a necked down width of B nearer to the apex of the lance. Because such necking down occurs often but irregularly and unpredictably, prior art lances 101, 103, 105 cannot be used to reliably locate and secure, for example, a hard drive chassis or a mount for securing a hard drive chassis within frame 100.